Variable condenser



March 15, 192?.

RODGERS ET AL VARIABLE CONDENSER Filed Sept. 24. 1924 s Sheets-Sheet 1 FlE-L J41 0011 tow THUS TRODGERS NARC A.G!BLIN PRI'XNCIS K. MOORE GEORGE Tw March 15, 1 927.

T. T. RODGERS ET AL VARIABLE CONDENSER THOS.T.ROD

GE RS MARC AGIBLHN MOORE GEORGE 'T. MOORE Mai-ch 15, 1927.

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' 7 Ourlinvention has reference',iiniits bread -aspect, to improvements, in "radio receiving apparatus of the type exennilified by mule tiple stage radio frequency amplification,

.' and more, p articular1 it is our-purpose to providea receiving apparatus fof this character whi ch maybe tuned byfthef 'inanipulmtion offa single medium. e v v In our co-p'endmg apphcatiolif Serial Number- 739,491,' filed September 24th; 192% for improvements in condensers, we, define particularly i the construction [of a. unique condenser-1. apparatus embodying condenser units having. a" common operatingmediumg in our present application, however, we ex tend the concept of the above identified apv e e .-byi finins th om at on t a multiple condenser assembly, mean s whereby such condensers are mounted, insulated' each :from the others, and manipulated;

In the present embodiment of our invention we' provide means whereby all of the stages ofradio'frequency amplification may be simultaneously tuned through the medium of a common instrumentality. Heretofore' it has been proposed to simultaneously tune the respective stages of radio frequency by' mounting the rotors of conventional ,multipleplate rotary condensers 9 upon a common shaft, but this has been foundimpractical for the reason that the sligqtest inaccuracy, distortion, imperfection orlhe like renders the system inoperative.

Y lVeYh'ave found, on the other'hand, that by utilizing air-dielectric condensers having two-opposed surfaces that the respective condensers for the several stages may be tuned simultaneouslyby altering the dielectric distance between the surfaces by equal incre-- me'n'ts. Furthermore, by combining in each stage of amplification ashielded 'magnetn rally balanced coil, such for instance'as theconventional Figure 8 coil. and one of the type of condensers before mentioned, all of the'disadvantages of conventional systoms of neutralized radio frequency are eliminated and a greatly improved and highly simplifiedradio receiving apparatus attaineth i The particular-elements of our radio receiving assembly employed to accomplish the above and other objects attributed to r it will'be hereinafterunore fully described -part of this specification. Y

in detail and pointed out I l clalms appended hereunto-and forming't a l6 In the accompanying drawings wherein we have illustratedvone of thepreferredembodiments of. our invention 2-.-

.Figureil is anelevation of the partlyin section, 5. Figure 2 is a-detail ofour recording and locking mechanism, and Figure 3.is a detail view,- partly-insection. of the detector unit and mea'nsifor holding our operating shaft in alignment. Like characters of referenceedesi gnate' like or similar parts throughout the several-views of the drawings, in which v A lesignates generally any desired form of cabinet in which our receiving apparatus may be mounted, and-B the top-thereof.

Suspended vertically from the top B of the cabinet is a frame generally designated, by

C which is formed with a transverse plate (1) having a central opening (2) andpins (3) which bear against the linden-side of the top B to holdithe plate and top; securely and rigidly together when the retaining screws (4) are sets" The top B is also formed so '-with a central,..opening registering withth'e opening (2) in the plate and withinrwhich extends the sleeve portion (5) of adi'sk .(6). Suspended from the plate (1) ofrthe frame are a plurality (preferably four) of vertical sectional'rods (7),,- which are removably secured to the plate by studs (8) said rods and late constituting the retaining elements 0 our receiving assembly. The

disk (6)]is disposed to rotate freely on the 90. top and is provided with a suitablehandle (9) for facilitating. manipulation of the .same. Beneath the top 13 and mounted for rotation with the, sleeve (5) is a-dial (10) the graduations thereon being arranged'to "pass beneath the peep opening (11) form'ed in the top for. visible inspection. Furthermore, the dial (10) "is'provi'ded with a pin (12) on its periphery which engages, upon each revolution of the dial, \vi one of the slots (17) in the indicating disk (13) the purpose of which is to indicate,- through another peep opening .f(14) ,the number of. v times the dial hasbeen rotated.

The sleeve (5) is interiorlyscrew-threaded. 105 (preferably 48 to the inch) and is adapted provided the aforementioned means whereby radio frequency receiving sets now found on the market. However, in addition to the foregoing wehave also provided means, as as been suggested, whereby inherent regeneration is neutralized or balanced in a manner not contemplated by other processes following out the rinciple of neutralized radio frequency. e substitute for all previously known neutralized radio frequency systems a shielded figure 8 transformer (D), having a frame (36), attaching members (43) and the usual binding posts (44).

One is used for each stage. It is understood that our shield may be applied to any coil and not necessarily to the present specific embodiment. It may here be said that the transformers are usua 1y tuned oradjusted but once, and that at the time the apparatus is assembled, thereafter all tuning is accomplished by the simultaneous manipulation of the condensers as has been described.

7 It is believed that the operation of our invention will be apparent from the foregoing description its various parts, but it is desired to emphasize the fact that we have not only provided a receiving apparatus of the multiple stage radio frequency amplification type wherein inherent regeneration is neutralized without the use of the conventional condenser connected from-the grid of one tube to the secondary winding of the next radio frequency transformer, but we have provided means whereby each stage is tuned simultaneously by the maniiulation of a single dial. \V hen the disk 8) is revolved the sleeve feeds the shaft axially whichvaries the dielectric between the respective condenser plates by equal increments thereby accomplishing not only accurate tuning but tuning of a high degree of selectivity.

lVhile in the foregoing, there has been illustrated and described such combination and arrangement of elements as constitute the preferred embodiments of our mvention, it is nevertheless desired to emphasize the factthat interpretation of the invention should only be conclusive when made in the light of the subjoined claims.

1. Radio tuning. apparatus, comprising a frame formed with insulating partitions each having an opening therein, an axially movable shaft extending through the openings in said partitions, a plurality of con denser units each having a fixed plate and a movable plate having the Whole of one of BEST AVAILABLECOM its surfaces opposed to the passive plate at all times, said movable plates being connected with the shaft for simultaneous movement to vary the distance between the plates of the respective condensers by equal increments, and means for independently adjusting said fixed plates.

2. In a radio tuning apparatus a plurality of condensers, one for each stage of radio frequency and one for the detector stage, sai condensers each having a movable plate for varying the distance between the plates,

axially movable means for adjusting said movable plates to vary the distance between the plates of all the condensers simultaneously and by equal increments, the portion of said condenser adjusting means common to the detector stage being insulated from the remaining portion, and means engaging said last named portion for maintaining said means in an aligned position.

3. In a radio tuning apparatus, a frame formed of a plurality of sections adapted to be connected together at their ends, a plurality of insulating plates, one adapted to be disposed between each of the sections and forming partitions dividing the frame into a plurality of compartments, an axially movable shaft extending from end to end of the frame through said partitions, a plurality of condensers, one plate of each condenser being carried by the shaft, the other plate of each of the several condensers being mounted on the respective insulating partitions, and means for adjusting said last mentioned plates independently with respect to the partitions for the purpose defined.

4. In a radio tuning apparatus a frame formed with insulating partitions, an axially movable shaft extending through said partitions, a plurality of condenser units each having a fixed plate and a movable plate, the fixed plate of each condenser being mounted on an insulating partition and provided with an opening through which the shaft is adapted-to extend, each of said fixed plates being beveled about the opening therein, the movable plates being connected to the shaft for simultaneous adjustment with respect to the fixed plates to vary the distances between the plates by equal increments, and means for independently adjusting the fixed plates with respect to the partions.

In testimony whereof we aflix our signatures hereunto.

- THOS. T. RODGERS.

MARC A. GIBLIN. FRANCIS K. MOORE. GEORGE T. MOORE. 

